This application claims benefit of Japanese Patent Application No. 2001-145544 filed on May 15, 2001, the contents of which are incorporated by the reference.
The present invention relates to a paper sheet stacking apparatus and, more particularly, to a paper sheet stacking apparatus for stacking paper sheets in upright state.
Post offices or the like use paper sheet stacking apparatus for stacking postal matter. FIG. 7 is a perspective view showing an example of paper sheet stacking apparatus disclosed in Japanese Utility Model Laid-Open No. 1-132643. As shown, paper sheets 180 are clamped between belts 181 and 182, and are transported to a space between a support plate 104 and a stacking roller 105 as the belts 181 and 182 undergo excursion. With increase of the paper sheets 190 stacked between the support plate 104 and the stacking roller 105, the support plate 104 is displaced away from the stacking roller 105. The paper sheets stacked in the paper sheet stacking apparatus is referred as paper sheet stack.
To the support plate 104 is applied a predetermined force toward the support plate 104. With the force applied to it toward the stacking roller 105, it clamps the paper sheet stack 190 between it and the stacking roller 105, thus supporting the paper sheets 190 to prevent turning-down thereof. The paper sheet stack 190 are stacked such that their stack relays on the support plate 104. With increase of the stack quantity of the paper sheets 190 a holder slide 107 is displaced along a guide bar 106.
To apply a predetermined force to the support plate 104, the holder slide 107 is pulled with a weight or a constant load spring (not shown in FIG. 7). The constant load spring is one which provides a constant force tending to cause its restoration to the initial length without spring elongation.
With the rotation of the stacking roller 105, each paper sheet 180 transported to the space between the stacking roller 105 and the support plate 104 is moved until its leading end 180a reaches a side plate 103. The paper sheet stack 190 thus has a neat leading end 190a aligned by the side plate 103.
The apparatus is preferably arranged such that each paper sheet 180 is transported to the space between the stacking roller 105 and the support plate 104 without its leading end 180a touching the trailing end 190b of the paper sheet stack 190. To this end, a belt (not shown in FIG. 7) is provided on the bottom plate 102 and driven for excursion to have the paper sheet stack 190 pushed against the support plate 104. FIG. 8 is a view showing a state that the paper sheet stack 190 is pushed against the support plate 104 by the belt. The belt 191 is provided such as to surround the bottom plate, and undergoes excursion on the top surface of the bottom plate 102 from the side of the stacking roller 105 toward the support plate 104. The paper sheet stack 190 formed upright on the belt 191 is pushed by the belt 191 against the support plate 104. Consequently, the leading end 180a of each transported paper sheet 180 difficultly touches the trailing end 190b of the paper sheet stack 190 and is thus smoothly stacked.
However, in the case of providing the belt 191 on the bottom plate 191 for pushing the paper sheet stack 190 against the support plate 104, a motor or the like for driving the belt 191 is necessary. To simplify the construction of the paper sheet stacking apparatus, the use of the belt 191 and the motor or the like for driving the belt 191 is undesired.
Besides, the support plate 104 supports the paper sheet stack 190 with a predetermined force applied thereto toward the stacking roller 105. Since the constant force is applied to the support plate 104 toward the stacking roller 105, and the support plate 104 supports the paper sheet stack 190 with a constant force irrespective of the increase of the volume of the paper sheet stack 190. On the other hand, the force, with which the paper sheet stack 190 tends to relay on the support plate 104, tends to increase with increasing volume of the paper sheet stack 190. Therefore, when the force of relaying on the support plate 104 by the paper sheet stack 190 exceeds the force, with which the support plate 104 tends to support the paper sheet stack 190, the support plate 104 can no longer support the stack 190, thus resulting in turning-down thereof.
When its leading end 180a reaches the side plate 103, the paper sheets 180 are stopped and stacked as the paper sheet stack 190. On the other hand, the stacking roller 105 is continuously rotated. This means that each stopped paper sheet is in contact with the rotating stacking roller 105 until the next paper sheet is transported. However, less time of contact of the paper sheet with the stacking roller 105 will be preferred.
An object of the present invention is to provide a paper sheet stacking apparatus capable of stacking paper sheets in the upright state with a simple construction.
Another object of the present invention is to provide a paper sheet stacking device capable of stacking paper sheets in the upright state irrespective of increase of the volume of the stack.
A further object of the present invention is to provide a paper sheet stacking apparatus capable of reducing the time of contact of each paper sheet to be stacked with a rotating member.
According to an aspect of the present invention, there is provided a paper sheet stacking apparatus for stacking paper sheets upright comprising: a bottom plate for stacking paper sheets being led upright; a side plate for stopping paper sheets led to the bottom plate; a rotary member rotated to intermittently touch the paper sheets being led and bring the paper sheets to the position of the side plate; a support member facing the rotary member and preventing the paper sheets being led upright from turning down onto the bottom plate; a guide bar, along which the support is moved to change the distance between the support plate and the rotary member; and a spring member pulling the support toward the rotary member; the bottom plate being slanted such that the paper sheets led upright into the apparatus are slanted toward the support.
The spring member provides increasing force tending to restore its initial length with its increasing elongation. With this construction, even with paper sheet stack volume increase, it is possible to prevent the turn-down of the stack which may otherwise occur when the support can no longer support the stack.
In the paper sheet stacking apparatus, a plurality of springs having different spring strengths pull the support toward the rotary member. The apparatus further comprises a stopper for stopping further elongation of the spring having less spring strength from a predetermined elongation, or a stopper disposed such as to determine the position, at which the spring having higher spring strength becomes active when the gravitational force of the stack due to volume increase thereof exceeds the spring strength of the spring having less spring strength. With this construction, when one of the spring members can no longer support the paper sheet stack, that spring member strikes the stopper, and the stack is supported by the other spring member. Thus, it is possible to prevent the turn-down of the stack.
The paper sheet stacking apparatus further comprises a wire having one end tied to the support and the other end secured at a fixed position and a movable pulley with the wire passed thereround, the spring member pulling the support toward the rotary member by pulling the movable pulley.
In the paper sheet stacking apparatus, as a plurality of spring members having different spring strengths are provided, the wire is passed round a plurality of movable pulleys, and each spring member pulls the support toward the rotary member by pulling each movable pulley. The apparatus further comprises a stopper for stopping further elongation of the spring having less spring strength from a predetermined elongation, or a stopper disposed such as to determine the position, at which the spring having higher spring strength becomes active when the gravitational force of the stack due to volume increase thereof exceeds the spring strength of the spring having less spring strength.
In the paper sheet stacking apparatus, the rotary member has two or more blades, each blade being capable of touching a paper sheet stack. In the paper sheet stacking apparatus, the blades of the rotary member each have an L-shaped free end.
In the paper sheet stacking apparatus, a guide for preventing the paper sheets being led from proceeding toward the rotation axis of the rotary member, and the guide has a window, through which the rotary member partly gets out the side of the support. With this structure, the paper sheets is prevented from proceeding toward the rotation axis, making it possible to smoothly stack the paper sheets.
In the paper sheet stacking apparatus, the bottom plate is higher in level on its side, on which the paper sheets are led into the apparatus, than the side with the side plate provided thereon. With this construction, the paper sheet led into the apparatus can be reliably led by the rotary member up to the side plate.
Other objects and features will be clarified from the following description with reference to attached drawings.